Cryptocurrencies were supposed to offer a secure, digital way to conduct financial transactions but they have been dogged by doubts. Concerns have largely focused on their astronomical gains in value and the likelihood of painful price crashes. Equally perilous, though, are the exchanges where virtual currencies are bought, sold and stored. These exchanges, which match buyers and sellers and sometimes hold traders’ funds, have become magnets for fraud and mires of technological dysfunction, posing an underappreciated risk to anyone who trades digital coins.
